IBM Pushes the Clock (Speed) on New Chips

Raw speed doesn’t seem to motivate many chip designers the way it used to. Not so at IBM.

The computing giant still sells lots of what the industry calls “big iron,” powerful machines designed to operate as a single system–not like the racks and racks of simpler servers that companies use for chores like serving up Web pages. IBM is disclosing details of two new chips for such high-end hardware, which exploit a technique that has lost favor in other parts of the market.

That approach boosts clock speed, or operating frequency, a performance measure akin to the revolutions per minute of a car’s engine. Chip giant Intel, after years of marketing megahertz and gigahertz improvements to PC users, started emphasizing other ways to boost performance in the last decade because of power consumption and heat worries. High frequencies are even more rare in chips for smartphones and tablets, where battery life is a key consideration.

But IBM keeps marching to a different beat. Its new version of the chip used in its venerable mainframe computer line–to be discussed at an upcoming technical conference in Silicon Valley this month–boasts a clock speed of 5.5 gigahertz, up from 5.2 gigahertz in the current version.

Big Blue is also updating the Power chip line, used in servers that run IBM’s variant of the Unix operating system. The existing Power7 chip comes with frequencies as high as 4.14 gigahertz; the next version, Power7+–also being discussed that upcoming Hot Chips conference–will be 10% to 20% faster, IBM says.

Of course, clock speed is just one of many factors shaping performance. Both IBM and Intel use such tricks as boosting the number of processors in chips and adding special-purpose accelerator circuitry for jobs like compressing or encrypting data. Another time-tested technique is adding massive caches of memory, with IBM stressing the use of a technology called eDRAM as a differentiating feature.

There are many other choices and tradeoffs. The new IBM mainframe chips draw up to 300 watts, for example, and the Power7+ up to 190 watts–compared to 130 watts for the comparable Xeon. Such comparisons can be misleading; IBM says large systems often can replace many smaller machines, so they actually save on electricity.

Other costs besides energy bills are relevant. Intel’s top-shelf Xeon lists for $4,616, for example, quite a lot for one piece of silicon. But Intel contends pricing for servers and some software licensing is much lower on Xeon-powered machines than Big Blue’s (IBM only sells chips as part of systems, so doesn’t price them separately).

The companies make conflicting claims about other topics, including the relative reliability of their chips. For now, however, their franchises are pretty secure in two largely separate businesses: Intel in the high-volume market for servers with one to eight chips, and IBM in “scale-up” systems, where as many as 32 chips at a time are used for chores like running huge databases.

“That is our principal value proposition,” says Satya Sharma, a fellow and chief technology officer for the Power line.